Introduce LLMClientApp type to remove xcode from MCP API swagger enum

[yrobla]

Summary

Xcode (GitHub Copilot for Xcode) supports LLM gateway but not MCP client registration. Previously declared as a ClientApp constant, it was included in the generated swagger enum for the MCP API, misleading consumers into attempting unsupported operations.

Introduce a separate LLMClientApp type for LLM-gateway-only tools and move the Xcode constant to it. The internal clientAppConfig entry uses an explicit ClientApp(Xcode) cast so the config table continues to work unchanged. Regenerate swagger docs to confirm xcode no longer appears in the enum.

Fixes #5073

Type of change

• Bug fix
• New feature
• Refactoring (no behavior change)
• Dependency update
• Documentation
• Other (describe):

Test plan

• Unit tests (task test)
• E2E tests (task test-e2e)
• Linting (task lint-fix)
• Manual testing (describe below)

API Compatibility

• This PR does not break the v1beta1 API, OR the api-break-allowed label is applied and the migration guidance is described above.

Changes

File	Change

Does this introduce a user-facing change?

Implementation plan

Approved implementation plan

Special notes for reviewers

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.79%. Comparing base (b470ddb) to head (6933b58).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5081      +/-   ##
==========================================
- Coverage   69.80%   69.79%   -0.02%     
==========================================
  Files         570      570              
  Lines       56919    56919              
==========================================
- Hits        39731    39725       -6     
- Misses      14139    14150      +11     
+ Partials     3049     3044       -5     

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[Copilot]

Pull request overview

This PR refactors client-type definitions to prevent LLM-gateway-only tools (specifically GitHub Copilot for Xcode) from being exposed as MCP-capable ClientApp values in the generated MCP API swagger schema.

Changes:

• Introduces LLMClientApp and moves the Xcode constant to this new type to keep it out of the swagger-derived ClientApp enum.
• Keeps internal config behavior unchanged by explicitly casting Xcode to ClientApp where needed.
• Regenerates swagger artifacts (swagger.yaml, swagger.json, docs.go) to remove xcode from the ClientApp enum.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pkg/client/config.go	Adds LLMClientApp, retypes Xcode, and casts to ClientApp in internal config table to preserve behavior while keeping swagger enums correct.
pkg/client/llm_gateway_test.go	Updates test to use ClientApp(Xcode) after retyping Xcode.
pkg/client/config_test.go	Updates switch cases to use ClientApp(Xcode) after retyping Xcode.
docs/server/swagger.yaml	Regenerated swagger output removing xcode from ClientApp enum.
docs/server/swagger.json	Regenerated swagger output removing xcode from ClientApp enum.
docs/server/docs.go	Regenerated embedded swagger template removing xcode from ClientApp enum.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

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